Alteration of potash-lime silicate glass in atmospheric medium: study of mechanisms and kinetics using 18O and D isotopes

Only a few studies deals with the alteration of glass by water vapor. This study aims to investigate mechanisms and determine kinetics potash-lime silicate typical Middle Ages. For that, model samples were exposed different conditions (relative humidity -RH-, temperatures) for several durations. The vapor used in experiments was enriched deuterium (D) oxygen-18 (18O). Results show that are highly temperature-dependent. At 50 °C, is driven interdiffusion, whereas at 20 mainly governed hydration without significant ion exchange. Then, isotopic profiles H, D, 18O 16O after sorption molecules surface, diffusing species matrix H+ or D+. Concerning kinetics, they evolve exponentially time first stages alteration. Moreover, follows linear trend below 83% RH strongly increases higher values.